Dr. Gregory Hahn is a pediatrician. He earned his medical degree and his specialty in pediatrics from the University of California, San Francisco School of Medicine in San Francisco, California. He is a board-certified pediatrician. He has been practicing medicine since 1977. He has been Chairperson of the Department of Pediatrics at the John Muir Medical Center for three terms. According to US News and World Report, his medical school, the University of California, San Francisco School of Medicine, is ranked 5th out of 144 in primary care quality. Dr. Hahn has offices in Alamo and San Ramon, California.